Taking advantage of the unique spectral characteristics of ternary complexes formed between amino acids, ferrous iron, and ferrozine, studies on the antioxidant activity of such complexes were continued. Decomposition of the ternary complex was found to occur by two independent pathways: (i) a non-oxidative pathway leading to formation of a ferrous iron-ferrozine complex and (ii) an oxidative pathway leading to ferric iron and colorless products. These processes were associated with occurrence of an isosbestic point (i.p.) whose wavelength varied from 601 to 574 nano meters, depending on experimental conditions. Results of simulation experiments, confirmed by direct analyses, demonstrate that the wavelength of the i.p. can be used to determine the fractions of ternary complex that are decomposed by the oxidative and non-oxidative pathways.